Utilization of sugar cane molasses for the production of dextran by Leuconostoc mesenteroides

Production of dextran by Leuconostoc mesenteroides 512 was investigated in static cultures using different sugar cane molasses as the carbon source in the culture medium. Refined molasses was the most favorable and effected 43.2% dextran yield and 73.0% fructose recovery. The age of culture from 12 to 48 hours had a limited effect on dextran yield, but a significant one on fructose recovery. Conversely inoculum sizes higher than 5% had adverse effect on dextran yield and did not significantly affect fructose yield or dextransucrase activity produced. Of the seven nitrogen sources investigated, corn steep liquor was the most favorable and effected 66.7% dextran yield. This indicated the use of sugar cane molasses and corn steep liquor as cheap carbon and nitrogen sources for the production of dextran. The results also indicated that Zn 2+ or Ca 2+ had adverse effect on dextran production

Production of alpha amylase by bacillus subtilis 1

Of 24 bacterial isolates, B. subtilis 1 was the most potent for the production of alpha-amylase. The highest yield of alpha-amylase was achieved by incubation of B. subtilis 1 for 40 hours at 45C. Addition of wheat bran, maltose, glucose or lactose to the culture medium had a stimulating effect on the production of alpha-amylase. The effect of various carbon and nitrogen sources on the production of the enzyme was also studied. The use of dipotassium hydrogen phosphate at 0.1-0.15% in the culture medium also favored enzyme production. Zn 2+ or Cu 2+ ions had adverse effect, but Ca 2+ ions and Tween-80 favored enzyme production. An initial pH of the cultural medium of 5.0 effected highest enzyme production [26.0 U/ml]

Purification and properties of ipomea batter B-amylase

Beta-amylase was prepared in a 33.4% yield from the homogenate of healthy, nongerminated sweet potato tubers. Beta-amylase in the cell-free extract was precipitated by ammonium sulfate fractionation [30-40%], chromatography on DEAE-cellulose and further purified by filtration on Sephadex-G 100. It has a specific activity of 1593.2 U/mg protein. No alpha-amylolytic activity was detected. The enzyme was active with starch, while being inactive towards sucrose, lactose and maltose. The Km value for beta-amylase was 2.63%. Optimal conditions for the action of potato amylase on soluble starch were at pH 5.5 and temperature 35-40C. The activity was completely inactivated by Fe 2+, Mg 2+ but EDTA, Ca 2+, Zn 2+, Cu 2+ and Co 2+ increase the activity of the enzyme by 2.1, 1.85, 1.75, 1.54, 1.51 fold, respectively. The molecular weight of the enzyme was estimated by gel filtration to be 64,000. The enzyme was relatively heat-stable, heating for 15 minutes at 40C resulted 14% loss of its activity

Preparation of beta-amylase from some Egyptian plants

Preparation Of beta -amylase enzymes from barely, soybean, sweet potato, potato, wheat flour and wheat bran was performed using different extracting agents. Sweet potato provided the most active beta -amylase preparation with water, saline solution or citrate-phosphate buffer [pH 4.8]. The effect of the pH value of citrate-phosphate buffer [pH 4.8] The effect of the pH value of citrate-phosphate buffer [pH.4.8] and concentration of sodium chloride on the extractability of beta -amylase from sweet potato were investigated. A pH of 4.8 of citrate-phosphate buffer and a concentration of 0.9% NaCI were the most appropriate for extracting beta -amylase of highest activity. Of all the enzyme preparations, that extracted with water at 30°C for 5 hrs. possessed the highest beta -amylase activity